Bristol Avon Flood Strategy consultation

Closes 20 Dec 2020

The risk of flooding to Bristol

Because of its location, Bristol is at risk of flooding from both the sea and the River Avon. There have been over 20 minor tidal floods in the last decade alone, the highest in March 2020 when properties and roads around the river were flooded including the A4 Portway.

Around 1,100 homes and businesses near the city centre and 200 properties in neighbouring communities are currently at risk of being flooded in either a severe river or tidal flood from the River Avon. This would have an impact across the west of England because of Bristol’s importance for jobs, transport, recreation, tourism and the economy.

Climate change is increasing sea levels and high river-flows, all of which increase the risk of flooding. If we don’t take action, by the end of the century nearly 4,500 existing properties could be at risk if there was a severe tidal flood.

The main causes of flooding from the River Avon in Bristol are:

High tidal surge

Storms can force water to surge in the Severn Estuary, creating a tidal flood up the river. Tidal flooding can be deep, fast flowing and hard to predict. The main risk to the city centre from the River Avon is from high tides combining with storm surges, where water rises over the top of low spots in defences, as well as causing water in the harbour to overflow and flood properties.

High river flows

Bristol is located at the bottom of a large 2,200km2 river catchment that drains land from the Mendip Hills to the south and the Cotswolds to the north. Heavy rainfall can increase river levels for days and this kind of flooding (fluvial) can be deep. Upstream of the St Philip’s area of Bristol, this is the main risk of flooding from the River Avon.

1. Before this consultation did you know that there was a risk of flooding from the River Avon?